Electric furnace.



G. H. BENJAMIN.

ELECTRIC FURNACE.

APPLICATION FILED DEG.19, 1913.

Patented Aug. 11, 19111 uw .NTF

, uw N NW .FWFMM @I UNITED STATES PATENT oEEicE.

GEORGE HILLARD BENJAMIN, NEW YORK, N. Y.

ELECTRIC FURNACE.

To 1li 'whom-it may concern:

Be it known that I, Grenen Hirmno BEN- JAMIN, a citizen of the UnitedStates, residing at New York city, in the county and State of New York,have invented certain new and useful- Improvements in Electric Furnaces,of which -the following especi-` ication.

My invention-relates to an improvement` operations taking place in thefurnace are more readily and perfect-ly accomplished,

than in prior constructions, andfurthei, the

etl'ect of the evolved gases neutralized and the action of free silicaupon the furnace walls avoidel. The accompanying drawings, which arelargely. diagrammatic, will serve to4 illustrate the main features ofthe construction of the furnace and also serve to aid in the descriptionof the method employed in operating the furnace.'

Referring to the drawings; Figure 1 is a vertical section of a furnacetaken on the line I-I of Fig. 2. Figf). is a vertical section taken onthe line II-II of Fi 3. Fig. 3 is a top view, with a portion -o thecover broken -away to illustrate one form of construction for the bottomof the Crucible.' Fig. 4 is avertical section taken on the v line IV'-1Vof AFigj, and Fig. 5 is a partial horizontal section illustrating` am0clitied form for the bottom ofthe Crucible.

in the drawings 10 indicates a closed magnetic core, madeofla'minatedplates and having the shape usual in transformer construction, that is,provided with a top i portion, 11. a bottom portion 12, side pori tions13 and a central portion 14. The core,

10 is mounted on channel irons 15, secured to rockers 16, which rockersare mounted on roller bearings 17,. located in the concave -the channelironsl 15 and arranged 'tiza sversely, are channel irons 19, and me.ntedonthetop of these channel irons is aringQO, poyided .with -anupwardiy projectin'g.l lrtion 21, ide for i.' of chauneled. rollers 22.and supported by'the late 20, is a diskshaped coil f supported on core1.0 is a i -Specification of Letterslatent.

Patented Aug. 11, 1914.

Application filed December 19, 1913.v Serial No. 807,684.

, con of-wire 24. These two coils fo'rm the primary circuit and areconnected in series to the terminals o f a source of alternating currentA. YSituated'over the coil-23 and .surrounding vcoil 2 4, is an annularcrucible 25. 'This cr'ncible .is mounted upon a. ring 26, having udependingportion 27,` which rests; upon the channeled rollers 22. On theoutside o f the hearth is a. metallic shell 28.'

29 indicates f. sectional cover for the top of the crucible.. i

acts as a hearth for the metal 'to be treated. .Qonnected tothe cavity30 at its inner periphery, are orts 31 connected with an an acts with a"channeled rin 33 supported above the 'coil 2 4, and whic ring, throughports 34,v communicates with ai pipe 35 whichinay be connected with apump or other similar apparatus (not shown) bv reason of which the gasesevolvedby th'e metal undertreatment may be exhausted, or conversely, orpowdered bodies introduced over t e metal on the hearth. Th'e metal onthe hearth is indicated by B,

. Ring 26,- which supports the Crucible, is provided with gear teeth 36on thelower lside ofv its periphery, which coact with a shaft 38. On theright hand end'of shaft 38 isa gear 39, which coacts with a'"worm 40 onashaft of motor 41.*- .It will-be understood that by reason of this lastdescribed arrangement, circular motion may be imiated by the motor 4L tothe Crucible 25.

j-IrnFigs. 3 and4 the bottom of the -c i'ucible @Bami-few trmsffrrmer,

-gear 37-mounted or: the .left hand end of4 and 'the ao. indicates@Cavity in the crue-ibi@ which nular channe shaped member 32which co-,ohearth 25 is provided with a' series of' be heated by induction to ahigh temperature. Further,l the metal being fluid, will be subject tothe repulsivel action of. thev primary current, and its surface willtake an angular inclination, as illustrated in 'Figf 1. Such angularinclination is objectionable,A

as the amountof'tluxemplloyednust be increased in accordance wit thedegreeyof inclination, i. e., the

ing the metal upon the hearth tothe action 'of a mechanical'f'orce, i.'e., the force exerted by the ribs 42 and 4?*,'whi'ch willv move thebottom of the metal inward or outward, and thereby not only reducethe'aiigularv inclination but create a circulation of`the metal -acrossthe heart-h and circumferentially within the hearth.

In practice I prefer'to rotate the crucible at a low speed, as forinstance, ten revolutions a minute, for say five minutes, and thenreversethemovement for a corresponding length of time. It `isdesirableto increase the speed as the 4fluidity' of the ma- My plan differstherefrom'in that the major portion of the furnace is fixedand'only theCrucible is rotated, thus requiring very muchv less power and permittinggreater facility of movement, and therefore a more perfect control ofcirculation of the material under treatment in the Crucible. Y

After the material and fluxes introduced i into the Crucible are heatedto the required temperature, I prefer toy exhaust the evolved gasesthrough the ports 31 and annular channel shaped member 32 and pipe 35.V

The object of doing this is two fold. First, to reduce the ressure ofthe evolved gases over the material under treatment'and thereby removeany reactive force tending to Vprevent free evolution of gas` andsecond, to instantly remove the evolved gases as generated, therebypreventing their reabsorption. Very many gases evolved from thetreatment of iron are liable to be split up into their elements whensubjected to the very high temperature of an electric furnace. as forinstance, siilfiireted hydrogen, in which case there is liability ofexplosion of the hydrogen and the rcincorporation of the sulfur with theiron, unless taken up by the slugs. The gases evolved will depend notonly upon the materials associated with -the. metals, but also upon thematerials assoreater the inclination" the greater amount` o' flux.Itisnitherefore desirable to decrease this inclination.,byi mechanicalmeans or otherwise. In practice I find the angularinclination maydecreased by rotating the cruoible and subject- What I wish to ciatedinthe fluxes or slags. These materials, owin to the high temperature andoxidizing actionto which they are subjected,

' will broken up or separated, some fthem risingto the te of the slaglevel, *as for instance, Si() w ich will attack thewalls of`ftlielaetiith,A thereby requiring frequent re- -newalsjofthewallsToloveicome this objectioii, I may introduce through the pipe B5,.annular channel shaped member 32, and

ports 31maghesitej(liIgOO3) which will combinevwithftliesilicon dioxidset free, and prevent-its destructive action.' Further, VI

-may intitoducexthrough the pipe 35,-annu-A lar channel shaped member32, and Orts 31,

aneiitral gassuch as nitrogen un er pressure, 'which' will prevent theaccess of atmosphericair from the exterior-,ofthe furnace to the meta-lunder treatmentor to the fluxes, and -thus'pievent oxidation, Or I mayin- :traduce :any gas, gaseous body or powdered body which willchemically combine'v with the fluxes, with the metal under treatment, orwith anybodies carried by the metal, such for instance as vthehydro-carbons, the ferro compounds,l titanium, magnesium, manga- `nese.or other metals.

I ,wish it understood that't s'within the contemplation of my inventionto introduce any' gas, liquid, powder, or combination of gases, liquidsorl powders, o'r allot them,

which may be found useful or desirable.

The 'cheinistry"ofA the bodies, such, as 'del scribed, undlerfthe hightemperatures of induction furnaces, is not now .-fully understood and Itherefore am unable to make a more t 'hnidafl' 'description of theactionsl 'and reactions whiclnit is desirable shall take place vin 'the4treati'nent of, metals of any' character or of slugs of any kind in aninduction furnace.

'believe I am the first to suggest the introducing into the Crucible.and the metal or have understood is that I under treatment, but throughthe material under treatment, as for instance, from bclow, as in themanner iii which air is introduced through the metal in a Bessemerconverter. I have not, in this application, described any specificconstruction, leaving it to be made the subject of an application to behereafter filed.

Having thus/ described my invention, I claim:

1. An induction furnace comprising a closed metallic core, a fixedprimary, a movable secondary formed by an annular crucible and a body ofmetal therein, together with means for rotating the secondary relative.to the core and primary.

2.*-An induction furnace comprising;r a closed metallic core` a fixedprimary, a movable secondary formed by an annular crucible and a body ofmetal therein, means for rotating the secondary relative to the core andprimary, and means communicating with the crucible for vexhausting gasestherefrom or introducing bodies thereto.

3. An induction furnace comprising a closed metallic core, a fixedprimary, a movable secondary formed by an annular crucible and a body ofmetal therein, means communicating with the. Crucible for exhaustinggases therefrom or introducing bodies thereto, and means for rotatingthe secondary relative to the core and primary.

4.` An induction furnace comprising a closed metallic Core, a fixedprimary, a movable secondary formed by an annular crixcible and a bodyof-metal therein, said crucibleliaving upwardly projecting,r ribs inthebottom thereof, together with means for rotating the secondary relativeto the core and primary.

5; An induction furnace comprising a closed metallic core, a fixedprimary, a mov- Copiel o! thl patent may be obtained able secondaryformed by an annular crucible and a body of metal therein, means forrotating,Y the secondary relative to the core and primary, said Cruciblehaving a sectional detacliable cover.

G. An induction furnace comprising a closed metallic core,A a` tilting,non-rotary primary, a rotary secondary formed by an annular Crucibleanda body of metal therein, together with means for rotating thesecondary relative to the core and primary.

7. An induction furnace comprising a closed metallic core, a non-rotaryprimary, a rotary secondary formed by an lannular Crucible and a bodyof. metal therein, ports and passages connected -to' said Crucible androtating therewith, a fixed pipe for the introduction o'f bodies into orthe withdrawal of bodies from the crucible operatively connected withsaid passages and said Crucible, together with means for rotating thecrucible relative to. the fixed portion .of the furnace.

In testimony whereof, I aix my signa- 'itnesses:

HELEN E. Kousen, C. A. HANssoN.

for five cents eachL by addressing the Commissioner ofv Intenta,

Washington, D. C."

